A technology has been used in recent years in which a product is imaged by a camera, which is an imaging device, in a production system, and a captured image is used for observation or inspection of the product. Patent Literature 1 discloses a technology that uses a sensor for detecting a workpiece reaching a detection position, as a device for triggering an operation of a camera. That is, the technology of Patent Literature 1 activates the sensor when a target workpiece being fed by a part feed system reaches an inspection position, and causes the sensor to output an output signal to a central processing unit (CPU) of a programmable logic controller (PLC). Upon detection of the output signal output from the sensor, the CPU activates a positioning mechanism to position the workpiece at the inspection position, and then causes the camera to perform image autofocusing control and to capture an image of the workpiece.